/**
 * @file Name: 3.cpp
 * @author: Fenghuwuyu
 * @version: 1.0
 * @brief:
 * @date: Fri 09 Apr 2021 02:54:05 AM PDT
 */

#include<iostream>
int main()

/**
 * when we created a container, we should consider build a "push_back" function to add new element into the container.
 *
 *
 */

/**
 * The std::initializer_list used to define the initializer-list constructor is a standard-library typo known to the compliler: when we use a {}-list, such as {1,2,3,4}, the compiler will create an object of type initializer_list to give to the program. So, we can write:
 * Vector v1 = {1,2,3}; // v1 has 3 elements
 *
 * Vector's initializer-list constructor might be defined like this:
 *
 * Vector::Vector(std::initializer_list<double> list):elem{new double[1st.size()]}, sz{1st,size()}
 * {
 *		copy(1st.begin(), 1st.end(), elem); // copy from 1st into elem
 * }
 *
 * so we can also learn keyword copy's using method.
 *
 *
